The intravenous infusion of various types of medicated fluids into patients has become an important part of the treatment of many different diseases. In addition, such multiple fluid infusion programs have also become an important part of the treatment of patients with trauma or patients injured in accidents. Such patients often receive their acute treatment in intensive-care units. In many institutions, immuno-suppressed patients such as bone marrow and other transplant patients also receive multiple intravenous fluids over a substantial period of time.
Depending on the physician's orders, these fluids are delivered to the patient by means of a surgically inserted, main-line catheter or at a peripheral site, such as the patient's arm or leg. Because of the condition of many of these patients, it is especially critical that the correct drug doses be administered at the correct rates during the designated periods of time. Further, many such patients become highly vulnerable to infections or may have depressed or damaged immune systems. Therefore, it is important to minimize, to the greatest extent possible, the potential entrance of infectious agents into the flow of fluids being administered.
Multiple fluid intravenous infusion has been practiced in the prior art by hanging containers of solution from an IV administration pole. The pole might be mounted on wheels to make it transportable. An initial solution is hung, and using aseptic technique is coupled to the patient's catheter. The nurse or other health professional adjusts the rate of flow by timing the rate of fluid drops falling in a drip chamber while manually adjusting a clamp valve.
To add a second fluid without adding another injection site to the patient, a fluid-flow junction, sometimes referred to as a "Y" site, or a "Y" junction is provided. This junction is located in the initial fluid-flow delivery tube. The second container of solution is coupled into an unused input of the "Y" junction. The rate of flow of the two solutions can be readjusted by means of manually operable clamps and drip chambers associated with each of the solution containers and by adjusting the relative heights of the containers.
If a third solution is required, a second "Y" junction it provided located in the administration line associated with the second fluid container is utilized. The third fluid-flow container is coupled into the second "Y" junction and the rates of flow are again, manually adjusted as before.
There have been a number of recognized problems associated with the above-described fluid-delivery systems. One immediate problem is the fact that use of gravity-flow and drop counting does not necessarily ensure that the desired flow rates to the patient will be maintained or will be sufficiently accurate. This is aggravated if the patient is to be moved such as for x-rays, cat scans or therapy. Such movement is difficult and cumbersome, while fluid is still being administered.
To overcome these problems it has become standard practice to use electrically powered infusion pumps which can be set to deliver a predetermined quantity of fluid through a fluid-flow conduit at a pre-determined rate. Such pumps lend themselves to portable usage. Usually they are mounted right on the fluid delivery pole, which is itself mounted on casters. Such pumps are often provided with battery back-up to provide portability and to provide several hours of uninterrupted service in case of main power failure.
Known prior art systems do not provide for appropriate automatic control of the various substances being delivered. In addition, multiple lines may need to be run between the patient and the plurality of infusion pumps to provide the necessary multiple drug therapy.
A step in the direction of attempting to deal with this problem is illustrated in U.S. Pat. No. 4,512,764 issued to Wunsch. The Wunsch patent provides for a plurality of fluid-flow solution containers which can be interconnected by a fluid-flow transfer set and a set of manually operative valves. Output from the manually operable valve system is coupled to a single fluid-flow conduit. This conduit passes through a peristaltic pump and then on to the patient. The manually operable valves are opened and closed at various periods of time to deliver the desired fluids.
In another patent, U.S. Pat. No. 4,559,036 also to Wunsch, a computer controlled set of valves is illustrated. The system of this latter Wunsch patent includes either motor activated or solenoid controlled valves which are connected to the control unit. Further, this system provides for a timing cycle, during which various valves are independently and successively opened for predetermined time intervals to permit the flow of various fluids to a patient.
Other multiple-fluid infusion systems have also been proposed which include various types of electronic control units. One aspect of any such system is the fluid-flow delivery set which is utilized in the apparatus. Some of the known delivery sets are relatively complex and expensive.
Extensive experience has taught that sterile, limited use, disposable, fluid-flow transfer sets can be cost-effective. Such sets can also be very effective in minimizing the possibility that infectious agents might inadvertently be delivered to the patient. However, such sterile limited-use, transfer sets do not in themselves solve the problem of controlling the infusion of a variety of different fluids to produce a desired composite fluid flow.
One known alternate is to use a multiplicity of infusion pumps, each coupled to one or more sets of solution containers. In this embodiment, two or more lines, each associated with a respective infusion pump, are brought to the patient and are coupled in an aseptic fashion to the patient. Such systems tend to be very flexible and are assembled at the patient's bed side. Nevertheless, they result in a cluttered, confusing system and represent substantial control problems from the point of view of the delivered fluid flow.
From a practical perspective, there is always a problem in any arrangement having multiple IV infusion poles, multiple pumps, multiple electrical cords and multiple sets of lines running from the containers to the pumps and from the pumps to the patient. When an attempt is made to move the patient, all of the poles must be moved in unison. This is not too difficult with one pole. It can be manageable with two poles. It becomes very difficult with three poles.
There is thus a continuing need for a closed, relatively portable uncluttered system which will provide for multiple, essentially simultaneous delivery of a plurality of different sterile fluids under sterile conditions. Preferably such a system would provide the ability to reduce potential contamination problems by reducing the number and complexity of tubes and junction members necessary to effectuate delivery of the fluids.
Such a system preferably would provide the ability to prepare planned medications and fluid-flow delivery sequences which would extend over substantial periods of time, such as 24 hours. Further, such systems would preferably utilize main-line catheters for the purpose of reducing the number of or eliminating various vein punctures usually necessary for the delivery process.
In addition, such a system should provide for the relatively long-term scheduling of delivered medications, such as over a 24 hour period. Further, such a system should provide assistance to the nursing staff of an institution in a variety of ways. The multiplicity of different infusion pumps should be reduced to the greatest extent possible.
The system should also be relatively user friendly and easy for the provider of care to work with. Further, such a system should assist in recordkeeping such as by generating hard-copy while at the same time being relatively silent in operation to avoid disturbing the patient and unobtrusive in function.